[Bug 1071011] [NEW] specific device not available in client (passthrough) with high cpu load on host, none in client

Gerben gerbgeus at gmail.com
Wed Oct 24 20:20:10 UTC 2012


Public bug reported:

I've got a specific device which is not always handed down to the kvm
client showing a high cpu load on the kvm host. No cpu load shown in the
client (win7).

A few (two) times I saw this device working properly with no high cpu
usage on the kvm host, but this was broken after a reboot of the KVM
host in at least one time. Reboots of the client showed the device
continue to work correctly multiple times before I rebooted the host.

06:00.1 Audio device [0403]: Advanced Micro Devices [AMD] nee ATI Cedar
HDMI Audio [Radeon HD 5400/6300 Series] [1002:aa68]

If the device works correctly, a device is shown by the device manager
within windows 7. If not no device is shown, while the host KVM process
consumes all cpu cycles assigned to it (2 cpu's in this case) and the
client shows not cpu power used.

My guess this is specific to this device (a sound device on the graphics
card, HD5440). The graphics device and an USB device in passthough both
work without problems.

When removing the sound device no high cpu usage is shown on the host.
Adding the sound device again, high cpu usage is shown on the host.


The host is a Quantal server installation.

# lsb_release -rd
Description:	Ubuntu 12.10
Release:	12.10
# apt-cache policy qemu-kvm
qemu-kvm:
  Installed: 1.2.0+noroms-0ubuntu2
  Candidate: 1.2.0+noroms-0ubuntu2
  Version table:
 *** 1.2.0+noroms-0ubuntu2 0
        500 http://nl.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: qemu-kvm 1.2.0+noroms-0ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu3
Architecture: amd64
Date: Wed Oct 24 21:59:10 2012
InstallationMedia: Ubuntu-Server 12.10 "Quantal Quetzal" - Release amd64 (20121017.2)
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-17-generic root=UUID=58e57f77-7117-4eff-8162-47b465a72050 ro
SourcePackage: qemu-kvm
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/12/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1102
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: SABERTOOTH 990FX
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1102:bd03/12/2012:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnSABERTOOTH990FX:rvrRev1.xx:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: To be filled by O.E.M.

** Affects: qemu-kvm (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug quantal

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https://bugs.launchpad.net/bugs/1071011

Title:
  specific device not available in client (passthrough) with high cpu
  load on host, none in client

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